What to do now
Mildest step first.
- Decide what comes in: rosemary, bay and basil need to; chives, mint, thyme and oregano usually winter fine outside.
- Hose off leaves and stems, check the pot's drainage holes for hitchhikers, and spray with insecticidal soap if you see pests.
- Over about a week, move pots from sun to light shade to heavier shade before bringing them in.
- Indoors, use a south-facing window or a grow light 14–16 hours a day, and water rosemary only when the potting mix is dry.
Which herbs to bring in
Not every herb needs to come in. Penn State lists rosemary as a tender perennial for zones 8 to 10, so in colder areas it needs to spend winter indoors, as does bay laurel, which is also commonly kept in pots and overwintered inside. Basil is a tender annual; UNH Extension notes it fails if it sits below 50°F for long, so either pot it up or take cuttings before the . Chives, mint, thyme and oregano are hardy perennials in most of the country. NC State notes that a layer of mulch protects mint and chives down to about -20°F. You can still pot a clump of chives or mint for the kitchen windowsill, but the plants in the ground don't need rescuing.
When and how to move them
Time the move by your . Penn State suggests bringing rosemary in 2 to 3 weeks before the first fall frost, so it adjusts before the furnace season starts. Bring basil in earlier, before nights cool toward 50°F. Plants that spent the summer in pots move most easily; UNH recommends starting with one that was container-grown all season. If you're digging from the garden, use a pot with drainage holes and fresh potting mix, not garden soil. Clay pots dry faster than plastic, which helps rosemary.
Check for pests first
Pests are the most common thing that comes in with herbs. Clemson's routine for any plant moving indoors: wash the leaves and stems with the hose, spray the whole plant, including leaf undersides, with insecticidal soap, wait a few days outside, spray again, and bring it in two or three days later. Slide the plant out of its pot to check for anything that crawled into the drainage holes. Rosemary indoors can pick up aphids, whiteflies, mealybugs, thrips and spider mites. Clemson also suggests easing plants into lower light over about a week, from sun to light shade to heavy shade, so the drop indoors is less of a shock. Some yellowing or leaf drop in the first weeks is the plant adjusting.
Light and temperature indoors
Indoors, light is usually the limit. Give herbs your sunniest window, ideally south-facing, and turn the pots every week or so. Basil and parsley need at least 6 hours of direct sun a day, according to UNH, or a full-spectrum grow light 14 to 16 hours a day. , stretched stems mean they aren't getting enough. Rosemary does best cool: UNH finds that a room around 45 to 55°F improves survival, and UW–Madison Extension suggests keeping it below 65°F and away from heat registers. Basil wants the opposite, 65 to 75°F by day and no lower than about 55°F at night.
Watering rosemary
Watering is where most indoor rosemary is lost. Overwatering causes root rot, which Penn State calls especially deadly in pots overwintered indoors; browning needle tips are an early sign. Check the mix about an inch down, water thoroughly when it's dry, and empty the saucer. Don't let the root ball go bone-dry either, since rosemary doesn't recover well from that. A cooler room means less frequent watering. A small fan or a spot with moving air helps against powdery mildew, which rosemary is prone to indoors, and rinsing the foliage every few days keeps spider mites down in dry, heated air.
Or take cuttings
If you don't have room or light for whole plants, take cuttings instead. Purdue notes that basil, oregano, rosemary, thyme and sage root easily from shoot-tip cuttings. For rosemary, Penn State suggests a 6-inch stem tip with the lower leaves stripped, in a warm spot around 70 to 75°F; roots tend to form in 10 to 20 days. A few rooted cuttings on a windowsill are easier to keep healthy than a large plant, and they can go back outside after your last spring frost.
Read the whole label first: it must list your crop, and its directions (amount, timing, gear, bees, days before harvest) are the law. If this page and the label differ, follow the label.
- RosemaryA tender Mediterranean shrub that some climates can overwinter and most cannot.
- Bay LaurelA Mediterranean tree that asks for patience and a place to winter indoors.
- BasilThe summer companion — to tomatoes, to pasta, and to the gardener with a south-facing window.
- ParsleyA biennial that gives you a year of leaves, then flowers and ends.
- ChivesA clumping perennial allium with purple pollinator-magnet flowers in spring.
- Why is my rosemary turning brown or dying?Most often it's too much water: rosemary roots rot in soggy soil, and browning tips are a common early sign. Check the roots and drainage first, then consider winter cold, dry indoor air, and powdery mildew.
- When and how should I harvest herbs for the best flavor?Harvest herbs before they flower — leaf essential oil concentration peaks right before flowering, and leaf production tends to decline once the plant shifts energy to seed production.
- Why are my basil leaves turning black?Basil leaves usually blacken from cold: nights below about 50°F, or a cold refrigerator, injure them. If yellow patches came first with gray fuzz underneath, it's downy mildew, and those plants should come out.